The invention relates to a device for labeling individual packages, in particular foodstuffs packages, comprising
a feed unit, for transport of the package particularly in horizontal direction
a weighing unit, arranged in the conveyance path, for weighing the package;
a printing device for printing a label detachably affixed to a carrier strip; and
an application unit for applying the printed label to the underside of the package.
Automatic labelling devices are used to apply labels to packages, in particular to foodstuffs packages, onto which among other information the price of the particular foodstuffs package is printed. From practical use, labeling machines are known which apply the label to the foodstuffs package from above in the conventional way. However, from practical use, automatic labeling machines are also known where the label is applied to the underside of the package.
DE 40 31 891 A1 discloses the labeling of the top and the underside of packages conveyed on a feed unit optionally with self-adhesive labels.
Carrying out labeling from below is becoming increasingly important because scanner cash registers read the price from an imprinted barcode. Since in particular in the case of meat packages this barcode should be applied to the underside of the packages, so as to avoid the need for turning the package over at the cash register, the label must be applied to the underside of the package. The provision of further product information such as e.g. use-by date or product number on the underside of the package is also desirable.
Such known automatic labeling devices for applying product labels to the underside of the package provide an aperture in the surface along which the package is conveyed horizontally. The label is fed from below though this aperture. The size of the aperture thus determines the maximum size of the label to be applied. There is a problem with such embodiments of labeling devices in that on the one hand the size of the label to be applied is limited and on the other hand the conveyance means for the package has to have a recess at the position of the aperture. This can lead to an interruption in conveying the package or a lateral displacement. In addition, the underside of the package needs to be flat to prevent it from getting stuck in the aperture or from falling into the aperture.
The state of the art is also set out in DE 32 23 477 A1, from which a machine is known with a transfer roller for applying self-adhesive protective labels to documents, file cards and similar.
It is thus the object of the present invention to further improve a device of the type mentioned in the introduction so as to reduce the likelihood of mislabeling.
According to the invention this object is met in that the application unit comprises a roller which during the application process of the label is driven so as to be synchronous with the package; with the printed label being removed from the carrier strip and, carried by part of the outer circumference of the roller, being able to be fed to the underside of the package; and with the point of labeling coinciding with the zenith of the roller and with the zenith of the outer circumference of the roller being arranged on a horizontal projection in the direction of conveyance of the package.
The roller is part of the conveyance system for the package, with the roller rotating synchronously with the package during labeling. Consequently, this solution is suitable for applying labels of any size to the underside of the package. In this, the package is not limited in respect to the shape of its underside; even curved or bent undersides can be provided with a label. Furthermore, the position of the label on the underside of the package can be freely selected, because the spatial allocation between the label printer and the position of the package is adjustable along the width of the roller. It is thus the central feature of the solution according to the invention that the label is no longer conveyed completely through an aperture, but is rolled onto the underside of the package from its front to its rear while the package is moving. The printer, in particular the thermal printer, is arranged at the underside of the system resulting in the label, once removed from the carrier roll, being fed from below to the package.
A further advantage is provided in that this arrangement makes it possible to combine the printing according to the invention from below the goods, with a further printer located above for labels on the top of the package. This provides the particular advantage that a first label containing information which is important to the customer, for example the price of the goods, is arranged at the top of the package, and the second label comprising the price in coded machine-readable form is arranged on the underside of the goods so as to be accessible by the bar code reader of the scanner cash register.
Preferably the roller used as an application unit is configured as a drum to which a suitably designed fan applies a partial vacuum. As a result of the partial vacuum, the label is held in place on the surface of the roller during the feed process to the underside of the package while at the same time not adhesively sticking to the roller surface. To this effect, in a further embodiment, the surface of the roller comprises a non-stick silicon coating.
Depending on the size of the labels to be applied, the surface of the drum comprises a greater or lesser number of perforations in an appropriate arrangement.
A further embodiment provides for the surface of the roller to comprise an indentation which interacts with a label catcher. In this way any labels adhering to the surface of the roller, which labels were inadvertently not taken up by a package, are removed by the label catcher which prevents a further rotation of the label.
This label catcher is positioned behind the labeling point, in the direction of conveyance.
If the label does not become completely detached from the carrier paper during printing, a label separation device provided according to a further embodiment, blows an airstream onto the wiping edge of the printer, thus causing the label to be separated from the carrier paper and to be blown in the direction of the labeling roller.
A further preferred embodiment provides for a support roller to be provided between the conveyance device and the labeling roller. The package moves over this roller which prevents rotation or shifting of the package during the transition between the conveyance device and the labeling roller. This roller is preferably made from a material with a soft surface, as is the labelling roller according to a further preferred embodiment.
A further embodiment of the invention provides for a further roller to be arranged behind the labelling roller. Preferably, this further roller is driven at a speed of rotation which results in the circumferential speed of the further roller exceeding the feed speed of the package. It is the purpose of this further roller to brush the label against the underside of the package after the actual labeling process thus counteracting any incomplete adhesion after the labeling process. If for example a corner is not flush, the label may be lost during further conveyance. The further roller is provided to prevent this.